A meshless method for stress-wave propagation in anisotropic and cracked media

Several transient wave propagation problems in anisotropic media and isotropic media with cracks are numerically analyzed by using a new numerical algorithm based on meshless local Petrov–Galerking (MLPG) method. In this algorithm, a novel modified Moving Least Squares (MLS) approximation is introduced to simplify the treatment of essential boundary conditions. By using a variant type of MLPG1 methods, the stabilized scheme of the discretized elasto-dynamic equations is obtained. Explicit central difference method with lumped mass matrix is used to solve the coupled ODEs to increase the efficiency of present algorithm. Visibility criterion is used to present the cracks, and the path-independent dynamic J′ integral is adopted to evaluate the dynamic stress intensity factors. The availability and accuracy of the present algorithm in solving dynamic problems in isotropic or anisotropic media with cracks are tested through the comparison with the results obtained by the LS-DYNA and the method of characteristic. Finally, the transient stress wave interacting with a slanted crack under an impact loading is investigated in detail, in which the ability of extracting the different stress-wave components in a complex acoustic field is also proved.